P – Glossary Terms



Protective, stable, lightly corroded, often smooth surface. Can either have formed naturally or through intentional intervention.


Damage to objects caused by insects, rodents etc., usually through staining, soiling, and consuming surfaces and organic components. Evidence includes Pest Residue such as casings and frass (dust-like debris left by wood-eaters) and Pest Damage such as exit holes, and grazing (partially eaten surfaces).



An area covered with low areas or depressions.

Porous (Ceramics/ Glass/ Stone):

Absorbent, will let moisture/dirt in. Easily crossed or penetrated.

Portable Antiquities Scheme:

The Portable Antiquities Scheme is a DCMS funded project to encourage the voluntary recording of archaeological objects found by members of the public in England and Wales. Every year many thousands of objects are discovered, many of these by metal-detector users, but also by people whilst out walking, gardening or going about their daily work.


similar to a face mask that draws dirt from the surface through an evaporation process.

Powdery (CGM/ Stone):

Corrosion in the form of tiny loose particles.


(paint layer) Loss of paint layer through loose or detaching powdery usually the result of insufficient quantity of binding medium in paint as originally applied, or a breakdown in the binding medium as result of deterioration.


implementing measures to aid in the long term care of materials e.g. climate control and pest management.

Preventive conservation:

This refers to actions which help to inhibit the deterioration of artefacts. This could relate to environmental conditioning or IPM (see above).



(textiles) Localised wrinkling and distortion caused by uneven tension and gathering of fabric often around embroidery.